1. Field of the Invention
The invention relates to a method for determining switchgear-specific data at contacts in switchgear, in particular contactor contacts, and/or for determining operation-specific data in a network connected to the switchgear or contactors, in which a so-called contact follow-through travel at a switching path is detected as an equivalent criterion for erosion, and a resilience change during a shutdown cycle is measured in each case to determine an erosion of contact facings of contact pieces and is converted to a remaining service life, for which purpose a time measurement of an armature movement from a start of the armature movement to a start of contact opening is carried out for a switchgear drive having an armature, a magnet coil and an associated yoke, wherein the armature movement is determined from the measured time, the resilience is determined therefrom, the measurement of the contact opening is detected on a load side of the monitored switching device and the armature movement start is signaled from the voltage of the magnet coil. The invention also relates to an associated apparatus for carrying out the method.
German Published, Non-Prosecuted Patent Applications DE 44 27 006 A1, DE 196 03 310 A1 and DE 196 03 319 A1 describe methods for determining a remaining contact life of contactors, in which contact wear, that increases over the course of the electrical contact life, is detected from a time difference between a start of the armature opening movement and a start of contact opening. A present value of the so-called contact follow-through travel is determined in that case with the aid of a microprocessor and specifically adapted electronic circuits for detecting required measurement variables, and reduces as a result of erosion from its new value (=100% remaining contact life) to its minimum contact life (=0% remaining contact life). The contact follow-through travel is defined as that movement distance through which the magnet armature travels between the start of armature opening and the start of contact opening during the shutdown cycle.